/Engine/Source/Editor/UnrealEd/Public/Kismet2/BlueprintEditorUtils.h
Blueprint has changed in some manner that invalidates the compiled data (link made/broken, default value changed, etc...)
static void MarkBlueprintAsModified ( [UBlueprint](API\Runtime\Engine\Engine\UBlueprint) * Blueprint, [FPropertyChangedEvent](API\Runtime\CoreUObject\UObject\FPropertyChangedEvent) PropertyChangedEvent )